Connective link between Annelida and Arthropoda.

1. Peripatus
Structure and Affinities
K.Kamatchi
Assistant Professor
Department of Zoology
Vivekananda College
Tiruvedakam West

2. •Arthropoda
•Class – Onychophora
•Living fossil
•Connective line between Annelida
and Arthropoda
•Discontinous distribution
•Warmer parts – Africa – malya

3. Salient features
Terrestrial
Moist, shady, bark of
dead trees
Nocturnal
Insectivorous
Caterpillar 1.5-15cm
Unsegmented
Part – segmented
Head, trunk

4. Antennae, eyes, oral papillae
Mouth – jaws
14-43 legs – claws
Anus
Covered – soft – velvety skin
Dermomuscular
Haemocoel
Straight – alimentary canal
Slime gland – prey – captured
Respiration – trachea –
spiracles
Excretion – metanephridia
Heart – long tube
Nervous system – ladder
Fertilization – internal
Development - direct

5. Affinities
• Guilding 1825
• Place – Mollusca
• Mosely 1874 – Arthropoda
Annelidan characters:
Segments – homonomous
Body – vermiform
Dermomucular
Legs – unsegmented
Eye – simple
Nephridia – segmentally
Genital duct – ciliated
Straight alimentary canal
Arthropodan characters:
Antennae – jointed
Jaws
Haemocoel
Ostia – heart
Tracheal system
Chitinous cuticle
claws
Unique characters:
Segments – not distinct
Ladder – nervous
Skin – soft
Wrinkles
Pair of jaws